Enh/use s3 instead of swift

[thomashbrnrd]

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[leihuayi]

@thomashbrnrd think of putting a comment on your PR next time please ;)

• remove all previous var for swift OS_... and replace by AWS_... in ci/cds
• use by default remote variables, in dev mode use minio
• update unit tests (remove testing the download of uploaded image since the url of remote image currently does not work - see TODO)

TODO:

• the image_url written in logs actually does not work: although the image is correctly uploaded in s3, the direct url link shows an error in browser :/ I asked the OVH team and according to them the url used in this PR is correct so I don't know what the problem is.
• I haven't managed to simulate the dev usage with minio locally, I don't know how it is supposed to work. It seems to fail since I don't have the log "Upload successful" when I try with minio instead of remote OVH s3.
• Add some verifications of whether the connection is successful. Write an error log if the credentials are incorrect to help for debugging (can use env variable WORKSPACE if necessary) but prevent failure of the application if that is the case = we want the app to run even if the photo upload fails.